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Author Topic: heavy lens problem Thomas Jonsson Expert Film Handler Posts: 216 From: Bromolla, Sweden Registered: Sep 2003 posted 09-23-2003 04:03 PM                       This is my first post here on the Forums, so first of all I would like to say HELLO to all of you. To the problem. I asked ISCO at ShoWest 2002 what lenses they would advice me to use to get the best possible image for Cinemascope. An UltraStar HD Plus(the red one)f=80mm and a BlueStar anamorphic attachment was the answer. So this is what I put into my two Cinemeccanica Victoria 5 projectors. However, those two lenses put together are not only long but also quite heavy. The result is this combination makes the lens turret spin around violently and smash the lenses into position, so I have had to turn the motor off and turn it manually. It also seems the length and weight makes the CS-lens dip slightly, resulting in a not uniformly focused image. The answer from Cinemeccanica: we can´t make a new turret just because ISCO makes heavy lenses. The answer from ISCO: Change back to your old lenses(THAT i won´t do). I will try to solve this by changing to a manual turret with a separate holder for the anamorphic. But it would be interesting to hear if anybody else have had this kind of problem?  |  IP: Logged Mike Perju Film Handler Posts: 90 From: Toronto, Canada Registered: Nov 2002 posted 09-23-2003 04:14 PM                     You can try the newer Schneider anamorphic lens... they are fairly light units.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 09-23-2003 04:54 PM                     Just how heavy are the ISCO red and blue lenses? I've been wanting to check them out, but haven't had the opportunity yet.  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 09-23-2003 06:44 PM                     well, you asked for the best possible image... an integrated anamorphic (if available in a size that works for you) would be a whole lot smaller and lighter and I haven't heard a lot of complaints about image quality.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 09-23-2003 10:18 PM                     I wouldn't consider those lenses heavy at all and they are the finest scope lenses made!! The old B&L scope lenses were quite heavy though and some early Simplex motorized turrets struggled to spin em into position. If it were my choice I'd get rid of the Cinemeccanniccas all together in favor of a real projector such as a Kinoton....... I always thought Sewdes were very quality concious... Volvo comes to mind...or are all you guys driving rusted out Fiats and shipping all the Volvos to the States??? Mark  |  IP: Logged Thomas Jonsson Expert Film Handler Posts: 216 From: Bromolla, Sweden Registered: Sep 2003 posted 09-24-2003 11:04 AM                       To Brad: I don´t know the exact weight, but a good guess is around 8 pounds, and a length of just over 11 inches. The lenses are really great, and I can strongly recommend them. To Dave: According to ISCO the red/blue combination gives a better image than the integrated anamorphic, so I think it´s a better idea to keep those lenses and do something about the lens mount. To Mark: When I bought new projectors 10 years ago, my first choice was Kinoton. The dealer, however, didn´t play fair and so the next choice was Vic 5. I must say to their defence, I´ve had no trouble with them up to now. In Sweden I guess the score between Kinoton and Cinemeccanica is fifty/fifty. And I think that goes for the rest of Europe too, possibly with the exception of Italy(!). I know what you mean with quality, Mark, and I hope to be able to put two of those in my booth later on...  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 09-24-2003 12:23 PM                        Thomas At a theater I worked on I have a very big and heavy ISCO cinemascope lens. I never had any problems, except that the focus usually was not perfect at lens change. On these projectors (1991) the lens' holder had to be registered because the rails that make the turret rotate was not perfectly adjusted and the turret itself was not perfectly hold. Let me explain: try to take in your hand the big ISCO lens. Try moving it up and down (do not force it too much!!!). Check if the lens is moving too much and, in that case, if what is moving is the len's holder or the entire internal ring of the turret. If the internal ring of the turret (the one that rotate, not the one solid with the projector) is moving there is the way to adjust it. What do you mean with "spin around violently and smash the lenses into position"? Vicoria's turret is not very gentle when rotating... Bye! A  |  IP: Logged Thomas Jonsson Expert Film Handler Posts: 216 From: Bromolla, Sweden Registered: Sep 2003 posted 09-24-2003 01:16 PM                       Hi Antonio. Nice to hear from Italy. I was recently in Rome, actually. Very, very, very nice town. It´s a 3-lens turret, and the problem occours when the lens(1.66:1) before the CS-lens is rotating into position. Then the CS-lens reaches it´s highest point and then start turning downwards. The weight of the lens makes the turret spin twice, if not three times, it´s normal speed and then smashes into position. In the long run this can´t be very healthy for the lens, or for the lens holder, regarding the heaviest part of the lens is farthest(right word?) away from the holder. There´s nothing wrong with the turret. I told the Cinemeccanica service-man in Sweden about this, and he didn´t really beleive me. So I told him to come and see for himself. He´s reaction when he saw it: -Det var som fan! In english: -What the ...?!!! He talked to Italy about it, and they came up with an idea of using some kind of counter-weights on the other two lenses, to achieve balance. I didn´t like the idea of increasing the entire weight of the turret, so I will try a manual turret with a separate holder for the anamorphic, and hope it does it...  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 09-25-2003 02:45 AM                     I'm not familiar with the Cinemecannica turret, but it seems like there are two ways to modify the turret that could help: a) Modify the turret to turn slower. This seems like it should be a simple electronics/control change. b) Add some mechanical elements that hold the lens more strongly. Perhaps a pair of 1cm steel rods tapped into the turret on either side of the relevent lens, and then a collar that clamped around the front of the lens that the steel rods were bolted to. Where is the center of mass of the lens with respect to the front edge of the turret? Could you post a picture (or even )? --jhawk  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 09-25-2003 04:14 AM                        Thomas If you set the holder of the interbal ring of the turret (I'm not sure I'm clear) tightening them a bit more the turret will be slower. On the manual (that I found on this site) pls check at page 35, part 5V-804/5/6. That is the tool that keeps the internal part of the turret (the one that rotate) on place. If you thight a bit this screws (there are three or four of that, do not tight only one! I'm not sure but perhaps you have to tight only the upper once otherwise you'll have to center again all the lenses) you should be able to make sufficient friction to slow the turret and make it more precise. The motor will stress itself a bit more but I don't think that it will damage itself since it spins only for few moments. But I'm not sure of this solution. I had a two lens holder when I had the big CS lens. I had absolutely no problem like you said, the speed of the turret was the same with both lens. You have a three lens holder so the weight has better balance than mine. I would check the turret registration. Let us know! Bye A  |  IP: Logged Thomas Jonsson Expert Film Handler Posts: 216 From: Bromolla, Sweden Registered: Sep 2003 posted 09-25-2003 01:07 PM                       Thank you all for good advice in this matter. The Cinemeccanica-guy in Sweden will visit me in a few weeks for service, and I will show him your suggestions and see what he thinks. Thanks again!  |  IP: Logged Ken McFall Jedi Master Film Handler Posts: 615 From: Haringey, London. Registered: Apr 2001 posted 09-25-2003 03:48 PM                     Hi Thomas... I've seen this myself with a three lens turret on a Vic 5. As the scope lens rises it slows the turret and as it falls it speeds up. Changing the speed of the motor etc is not really practical. The counter weight idea seems the most practical. The turret does very little work in the course of a day so the extra weight is not going to be a real problem. Trying to balance it so the difference is not too significant seems like a good idea.... as to how you do it is another matter! I should add that most turrets are a little jarring in the way they work. The early Kinoton turret worked at two speeds. Fast then slow as the lens reaches its stop position. Newer turrets are single speed and do stop with a jolt. Their aim is to give a very quick feature change... in the region of a few seconds. Slower turrets would mean a much longer blank period on the screen. I would suggest you check that eveything is tight on the turret and make sure there is no play on the three bearings that the turret rotates on.  |  IP: Logged Antonio Marcheselli Phenomenal Film Handler Posts: 1260 From: Florence, Italy Registered: Mar 2000 posted 09-27-2003 06:57 AM                        A lens like this one? Bye A  |  IP: Logged Thomas Jonsson Expert Film Handler Posts: 216 From: Bromolla, Sweden Registered: Sep 2003 posted 09-28-2003 04:48 AM                       Hi Antonio Yes, something like that. I used to have the gold series lenses from ISCO, like the ones in your picture, and with those there were no problem. But the red lens combined with the BlueStar anamorphic are longer and perhaps 50% heavier. It seems to be just too much weight for the turret. But I´m still curious to hear if somebody else have had this kind of problem, perhaps with other projectors?  |  IP: Logged

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